Beaconless adaptive optics system

Abstract

An improved beaconless adaptive optics system and process. A target is illuminated with a high energy laser beam of a directed energy laser. Wave front measurements are made of high energy laser beam reflections from the target. These wave front measurements are analyzed by a high speed processor to determine both high frequency phase components and low frequency phase components in the wave front data. (Applicants' experiments have shown that there is a direct correlation between beam spot size on the target and the phase variance of the reflected laser beam. The correlation is: the greater the phase variance the smaller the beam spot size.) Applicants have developed a technique for providing special control algorithms that provide very high speed control of the elements of a deformable mirror using this phase variance as a feedback parameter. Applicants have also developed algorithms to correct a limited number of Zernike modes associated with the wave front control.

1. An adaptive optics system comprising:
 A) a laser system, comprising a laser and a deformable mirror, adapted to illuminate a target with a high energy laser beam corrected for atmospheric distortion, 
 B) a wave front sensor adapted to measure wave fronts of beams reflected from the target, 
 C) a controller adapted to control components of the deformable mirror, and 
 D) a high speed computer processor programmed with an algorithm adapted to analyze frequency components in the reflected beams measured by wave front sensor, to calculate phase variances of the reflected laser beam and to use the calculated phase variance values as feedback values to iteratively control segments of the deformable mirror in order to compensate for atmospheric distortion and to minimize laser spot sizes on the target; wherein said high speed computer processor is also programmed with an algorithm adapted to correct a limited number of Zernike modes associated with the wave front. 
 
     
     
       2. The system as in  claim 1  wherein said wave front sensor is positioned off axis. 
     
     
       3. The system as in  claim 1  wherein the laser is a high energy laser adapted to produce sufficient energy to destroy the target. 
     
     
       4. The system as in  claim 1  wherein the system is adapted to function as a target designator. 
     
     
       5. A process for illuminating a target through atmospheric distortion with a high energy laser comprising the steps of:
 A) directing a high energy laser beam produced by a high energy laser system to a deformable mirror system adapted to redirect the laser beam through an atmosphere to a target, 
 B) monitoring laser beams reflected from the target to determine phase variances in the reflected beams, 
 C) analyzing the phase variances with a high speed computer processor programmed with an algorithm for analyzing frequency components measured by wave front sensor to calculate phase variance of the reflected laser beam and using the calculated phase variance values as feedback values to iteratively control segments of the deformable mirror in order to compensate for atmospheric distortion and to minimize laser spot sizes on the target; wherein said high speed computer processor is also programmed with an algorithm for correcting a limited number of Zernike modes associated with the wave front.